The following documents disclose continuous processes for producing peroxyacids or the like from hydrogen peroxide, sulfuric acid, and a carboxylic acid: U.S. Pat. No. 2,816,147, issued to Weber et al on Dec. 10, 1957; U.S. Pat. No. 3,140,312, issued to Kurhagec et al on July 7, 1964; U.S. Pat. No. 4,087,455, issued to Prescher et al on May 2, 1978; Canadian Pat. No. 744,391, issued to Wenzke, et al on Oct. 11, 1966; and U.S. Ser. No. 895,411, filed by Camden et al on Apr. 11, 1978 (the latter application is owned by the owners of the present application).
Numerous prior art references indicate the problem in the prior art of performing the present reaction safely, since if the reaction is not carefully controlled it can become uncontrollable, resulting in an exothermic reaction or even an explosion, or at least in an obstruction of the passages of the reaction apparatus. There is no recognition that use of a liquids:solvent ratio of greater than about 20:1 will provide that safety.